枢轴列下的数据透视表字符串分组？

Question

JOB        ENAME
--------  ----------
ANALYST    SCOTT
ANALYST    FORD
CLERK      SMITH
CLERK      ADAMS
CLERK      MILLER
CLERK      JAMES
MANAGER    JONES
MANAGER    CLARK
MANAGER    BLAKE
PRESIDENT  KING
SALESMAN   ALLEN
SALESMAN   MARTIN
SALESMAN   TURNER
SALESMAN   WARD

我想格式化结果集,以便每个作业都有自己的列:

CLERKS  ANALYSTS  MGRS   PREZ  SALES
------  --------  -----  ----  ------
MILLER  FORD      CLARK  KING  TURNER
JAMES   SCOTT     BLAKE        MARTIN
ADAMS             JONES        WARD
SMITH 

我试过了

SELECT ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN from
(
  SELECT ename, job from emp
) as st
pivot
(
  SELECT ename
  FOR job in (ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN)
) as pivottable

我收到这些错误

消息156,级别15,状态1,行7
关键字'SELECT'附近的语法不正确.
消息156,级别15,状态1,行8
关键字'in'附近的语法不正确.

如何使用数据透视表在枢轴列下分组字符串？

Answer 1

使用该PIVOT功能时,您需要使用聚合功能.a的语法PIVOT是:

来自MSDN:

SELECT <non-pivoted column>,
    [first pivoted column] AS <column name>,
    [second pivoted column] AS <column name>,
    [last pivoted column] AS <column name>
FROM
    (<SELECT query that produces the data>)
    AS <alias for the source query>
PIVOT
(
    <aggregation function>(<column being aggregated>)
FOR
[<column that contains the values that will become column headers>]
    IN ( [first pivoted column], [second pivoted column],
    ... [last pivoted column])
) AS <alias for the pivot table>
<optional ORDER BY clause>;

使用字符串,您将需要使用MIN()或MAX()聚合函数.您将遇到的问题是这些函数将为每列返回一个值.

因此,为了使其PIVOT工作,您需要提供一个独特的值,以便在行期间保持行分离GROUP BY.

对于您的示例,您可以使用row_number():

SELECT ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN 
from
(
  SELECT ename, job,
    row_number() over(partition by job order by ename) rn
  from emp
) as st
pivot
(
  max(ename)
  FOR job in (ANALYST, CLERK, MANAGER, PRESIDENT, SALESMAN)
) as pivottable

请参阅SQL Fiddle with Demo.

在row_number()创建分配给每个行中的一个独特的价值job,当你申请的聚合函数和,GROUP BY在PIVOT你仍然会得到不同的行.